STIMULUS ASPECTS OF AVERSIVE CONTROLS: THE RETENTION OF CONDITIONED SUPPRESSION.
Fear learned with a tone can last 30 months yet keeps weakening each time it is tested without the shock.
01Research in Context
What this study did
Pigeons first learned to peck a key for food. A tone always came before a short shock. Soon the birds stopped pecking when they heard the tone.
The researchers waited 2.5 years without any shocks. Then they tested the birds again. They played the old tone and new tones to see if fear came back.
What they found
After 2.5 years the birds still froze most at the old tone. The fear had not vanished.
Each test made the fear weaker. More trials meant more pecking returned. When extra shocks were given the fear popped back for a short time.
How this fits with other research
Hoffman et al. (1966) trained birds with two tones, not one. They saw two fear peaks instead of one. Both studies show tones gain tight control over fear.
Oliver et al. (2002) also watched behavior die out with repeated tests. Their children with pica stopped mouthing items when the payoff disappeared. Same rule: no payoff, behavior fades.
Okouchi (2003) moved the work to humans. College students showed the same slanted generalization curve first seen in these pigeons. The shape of fear spread is not just a bird thing.
Why it matters
Old fear can sit quietly for years and still return. When you fade aversive stimuli keep testing. Each safe trial chips the fear away, but one new shock can revive it. Plan longer extinction runs and guard against surprise aversive events.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Probe the feared sound twice, then run ten safe trials and watch the response drop.
02At a glance
03Original abstract
Three years ago a tone ending in unavoidable electrical shock was periodically presented to pigeons while they pecked a key for food. When pecking was disrupted by tone, shock was disconnected and the training tone as well as tones of different frequencies were presented. At first, all tones caused a reduction in the rate of pecking, but as testing proceeded, suppression began to extinguish and the gradient narrowed. In the present work, testing was resumed after a 2(1/2)-yr interruption. Analysis of the gradients obtained just before and just after the interruption yielded no evidence of changes with the passage of time. As testing proceeded, however, extinction of suppression continued and the gradient all but disappeared. In subsequent experiments with these subjects (Ss) it was found that the presentation of free shocks caused a reappearance of the gradient and that this effect persisted in reduced amount for several sessions after the shock condition was terminated.
Journal of the experimental analysis of behavior, 1963 · doi:10.1901/jeab.1963.6-575